How sandeepsilumula/terraform-universal-template works
1. This repository is an AWS infrastructure-as-code template built with Terraform. The root of the repo is the orchestration layer; the actual infrastructure is split into reusable modules under modules/.
2. The architecture is organized into three main subsystems:
- modules/networking for network foundation
- modules/security for access control / protection boundaries
- modules/compute for the workload host(s), likely the EC2 layer given the SSH instructions in the README
3. The root Terraform files (main.tf, variables.tf, outputs.tf, providers.tf) act as the composition layer. They wire the modules together, define shared inputs, configure the AWS provider, and publish top-level outputs for consumers and operators.
4. backend.tf indicates remote state management. The README says state is stored in S3 with a DynamoDB lock table, so the infrastructure depends on external AWS services for shared state, concurrency control, and safe team usage.
5. environments/dev/terraform.tfvars shows the repo supports environment-specific configuration. The environment folder is the boundary for deployment-specific values, while the modules remain reusable across environments.
6. The networking module is the foundation layer. In a typical AWS template like this, it is where VPC-level resources, subnets, routing, and internet connectivity are defined. Other modules depend on it to attach compute into the correct network.
7. The security module represents the access and isolation boundary. In practice this usually means security groups and related permissions that control who can reach the compute layer and on what ports.
8. The compute module is the runtime workload layer. The README’s SSH instructions and public IP lookup strongly suggest it provisions at least one EC2 instance and exposes connection details through module outputs.
9. Data flow is top-down: environment variables and terraform.tfvars feed root variables, root configuration passes those values into the modules, modules create AWS resources, and root/module outputs surface things like instance IPs or other connection endpoints.
10. Operational flow is CI-driven. .github/workflows/terraform.yml indicates Terraform runs through GitHub Actions, with AWS credentials supplied via GitHub Secrets. The intended deployment path is push-to-main, which triggers provisioning automatically.
11. The repo also has a clear human/operator boundary: after deployment, operators retrieve the instance IP from GitHub Actions logs and connect directly by SSH. That implies the system exposes a public entry point rather than hiding compute behind an application tier.
12. For an architecture diagram, the key relationships are:
- GitHub Actions -> Terraform
- Terraform root -> remote state backend in S3/DynamoDB
- Terraform root -> networking/security/compute modules
- networking/security -> compute as dependencies
- compute -> public SSH access for operators
Main entry points: main.tf Terraform root · compute/main.tf Compute · networking/main.tf Networking · security/main.tf Security
Components 18
Orchestration
Root Terraform files that compose the stack and expose shared configuration.
- Terraform root · Top-level Terraform entrypoint that wires the modules together.
main.tf - Providers · AWS provider and account/region setup.
providers.tf - Backend · Remote state configuration for shared Terraform state and locking.
backend.tf - Variables · Shared root inputs passed into the stack.
variables.tf - Outputs · Top-level values published for consumers and operators.
outputs.tf
Environment
Deployment-specific values for a given environment.
- Dev tfvars · Environment-specific deployment values for development.
environments/dev/terraform.tfvars
Modules
Reusable infrastructure subsystems built under modules/.
- Networking · Network foundation: VPC, subnets, routing, and connectivity boundaries.
modules/networking/main.tf - Network outputs · Networking values consumed by downstream modules.
modules/networking/outputs.tf - Security · Access control and isolation boundary for the workload.
modules/security/main.tf - Security outputs · Security boundary values shared with compute and root outputs.
modules/security/outputs.tf - Compute · Workload host layer; likely provisions the reachable EC2 instance.
modules/compute/main.tf - Compute outputs · Connection details such as public IP or SSH endpoint.
modules/compute/outputs.tf
Automation
CI workflow that runs Terraform.
- GitHub Actions · Automated Terraform execution on repository events.
.github/workflows/terraform.yml
External AWS
AWS services used by the template and its remote state.
- AWS state · Remote backend services for shared state and lock coordination.
- AWS network · AWS infrastructure resources created by the networking module.
- AWS security · AWS access controls created by the security module.
- AWS compute · Provisions the reachable workload host.
Operators
Human access path after provisioning.
- SSH access · Direct operator access to the instance after deployment.
Connections 20
- GitHub Actions → Terraform root: runs · GitHub Actions invokes Terraform to plan/apply the stack.
- Dev tfvars → Variables: fills · Environment tfvars provide values for root variables.
- Terraform root → Providers: uses · Root composition is built against the configured AWS provider.
- Terraform root → Backend: stores state · Root Terraform uses the remote backend for shared state.
- Backend → AWS state: backed by · State is stored in S3 and locked with DynamoDB.
- Terraform root → Variables: reads · Root module consumes shared inputs.
- Terraform root → Outputs: publishes · Root module exposes stack-level outputs.
- Terraform root → Networking: composes · Root wires in the networking subsystem.
- Terraform root → Security: composes · Root wires in the security subsystem.
- Terraform root → Compute: composes · Root wires in the compute subsystem.
- Networking → AWS network: provisions · Networking module creates the AWS network foundation.
- Networking → Network outputs: exports · Networking module exposes network identifiers and connection values.
- Security → AWS security: provisions · Security module creates AWS access controls and boundaries.
- Security → Security outputs: exports · Security module exposes boundary values for other modules.
- Compute → AWS compute: provisions · Compute module creates the workload host.
- Compute → Compute outputs: exports · Compute module exposes connection details.
- Networking → Compute: feeds network · Compute depends on the network foundation.
- Security → Compute: guards · Security boundaries control access to compute.
- Compute outputs → SSH access: enables · Compute outputs give operators the SSH target.
- GitHub Actions → AWS state: reads state · Automation relies on the remote backend during runs.